Incandescent electric lamp.



W. G. HUGHES.

INGANDESCENT ELECTRIC LAMP.

APPLICATION FILED DEO.18, 1012.

1, 1 05,908. Patented Aug. 4, 1914,

IN VEN T 0R 7/1 g i y us Al/orney UNITED STATES PATENT OFFICE.

WILLIAM G. HUGHES, 0F PITTSBURGH, PENNSYLVANIA.

INCANDESCENT ELECTRIC LAMP.

Specification of Letters Patent.

Patented Aug. 4, 19121..

Application filed December 16, 1912. Serial No. 737,089.

be so constructed and arranged as to provide for a relatively long filament in a relatively short space, or in other words, to provide for an increased length of filament without increasing the length of the glass bulb.

A further object of the invention is to so construct and arrange the filament in an incandescent lamp as to equalize vibration or jar and thereby reduce danger of fracture of the filament to a minimum.

,A still further object is to provide a filament of chea and simple construction, durable and e ective, and by which an increased candle power from the same size bulb may be obtained.

With the above and other objects in View, the invention consists in the novel construc tion, combination and arrangement of parts as will be hereinafter more specifically described and thenclaimed, and in describing the invention in detail, reference will be had to the accompanying drawings illustrating an embodiment of my invention, wherein like numerals of reference will be employed to designate like parts throughout the different views, and in which Figure 1 is a side View of an incandescent bulb provided with my invention, and, Fig. 2 is a detached and enlarged fragmentary view in perspective of a part of a filament in accordance with my invention.

The bulb 5 of the lamp may be of any ordinary or suitable construction though I preferably make the same slightly larger r at the plug end thereof as shown in the illustrated embodiment so as to admit a mount 6 of substantial construction, throu h which mount the leads 7 are passed in t e usual way.

The filament 8 may be of any desired material, the invention broadly consisting in the particular formation of this filament. Said filament is relatively long, and in order that it may be contained in a bulb of ordinary size is formed spirally throughout its length, the convolutions at the apex while being of the same diameter as the remaining convolutions being closer together, since the vibrations imparted to the filament by jars on the lamp are support. Thus the anger of fracture of the filament at this point are reduced to a minimum.

eatest at its point of l To steady and support the filament, I

provide an anchor post 9 generally made of translucent material and which extends from the mount 6 and may or may not be formed integrally therewith. A wire extension 10 extends from the outer end of this anchor post and is connected: at its outer end to the central convolution of the coils at the apex of the filament. The forming of the filament throughout its length into coils, the convolutions of which are but slightly separated throughout the length of the filament, and which convolutions at theapex of the filament lie closer than through out the remainder of the filament, has been found to equalize the vibration strains to which the filament is subjected and minimize the danger of fracture, while the increased length of filament'thus obtained provides for an increased light without increase of 4 bulb size.

I claim is 1- 'The improved electric incandescent lamp comprising a glass bulb, a filament wound spirally throughout its length with the convolutions at the apex of the filament in closer relation than throughout the remainder of its length, and means for bracing the filament. w

In testimon whereof I atlix my signature in presence 0 two witnesses.

WILLIAM G. HUGHES.

Witnesses:

IDA L. SHEnnnn, IONA WAGNER. 

